It's not the coverage; that's mostly good. It's not the price; mostly SIM cards and plans are cheaper when travelling than they are at home. It's the hassle of swapping SIMs every time you cross a border.
As of this year I ditched my T-Mobile prepaid data SIM and exclusively use prepaid eSIMs (esimdb.com has a great comparison, but Nomad makes it very easy with their app). So I still have to "swap sims" but it's all done on the iPhone itself, no need to bring a sim ejector/paperclip.
What's really funny is that last week my eSIM ran out (I forgot to top up) and my 16 Pro connected to the satellite network (since it assumed no service was available I guess?), where I was able to use iMessage (in the limited way (to individuals, not groups)).
Which isn't really a negative to this. Indeed, if you have the means, I'd say go for it.
Personally, I still buy SIM cards (or, more recently, eSIM plans). Not so hard, but way cheaper, and you can get a local number and use with local services that require one.